Source : Webster's Revised Unabridged Dictionary (1913)

Petulant \Pet"u*lant\, a. [L. petulans, -antis, prop., making
   slight attacks upon, from a lost dim. of petere to fall upon,
   to attack: cf. F. p['e]tulant. See {Petition}.]
   1. Forward; pert; insolent; wanton. [Obs.] --Burton.

   2. Capriciously fretful; characterized by ill-natured
      freakishness; irritable. ``Petulant moods.'' --Macaulay.

   Syn: Irritable; ill-humored; peevish; cross; fretful;
        querulous.

Source : WordNet®

petulant
     adj : easily irritated or annoyed; "an incorrigibly fractious
           young man"; "not the least nettlesome of his
           countrymen" [syn: {cranky}, {fractious}, {irritable}, {nettlesome},
            {peevish}, {peckish}, {pettish}, {testy}, {tetchy}, {techy}]